You're a 15-minute drive from Artesia, which has more Indian food than anywhere else in SoCal. My personal favorites are Tirupathi Bhimas and Woodlands, but scan the boards and you'll find some other recs.

For the twenty-person lunch, I assume you're looking in Whittier. What price point? For a nice lunch, I'd suggest Dal Rae because they do well with groups. But there are some other options... You could go to El Camino for their chicken fajitas, North Woods Inn for steak, Golden Triangle for Burmese/Thai, etc.